If one of the computers has a printer attached, then the other computer can print to it over the network.

If one of the computers has certain files on it, someone on the other computer can access those files over the network rather than having to copy them onto a disk or memory stick.

If you like playing multi-user computer games that have network capabilities built in, then two people can play these games together over the network.

If you connect to the Internet with one of the computers, the other computer can use that same connection over the network. So one computer can connect to the Internet with a modem and the other computer will route its Internet traffic through that single connection.

Networking PCs has gotten easier and a lot less expensive, but it is still a little bit of a challenge. How Home Networking Works discusses the whole thing in detail, but see the next page to see some quick answers.